Cryosurgical device



1, 1957 R. 0. JOHNSTGN 3,3335%? CRYOSURGICAL DEVICE Filed m. 28, 1965INVENTOR ROBERT D. JOHNSTON 50 ATTORNEY United States Patent O 3,333,587CRYOSURGICAL DEVICE Robert D. Johnston, Brownsbnrg, Ind., assiguor toUnion Carbide Corporation, a corporation of New York Filed Jan. 28,1965, Ser. No. 428,724 10 Claims. (Cl. 128-3031) This invention relatesto cryosurgery devices and particularly to such devices adapted toconduct a refrigerant to a surgical tip member regardless of theattitude of the device.

Known cryosurgery devices comprise a source of refrigerant, a surgicaltip member, and means such as a vacuum-insulated hose to transport therefrigerant from the source to the tip member. For some purposes, theelongated refrigerant transfer means is cumbersome and could be aserious handicap. One such purpose is cryosurgery on opthalmic tissueswhere the surgical tip must be easily manipulatable.

An object of this invention is to provide a compact cryosurgery devicewhich incorporates a refrigerant source and a surgical tip member withinone body. Anotherobject is to provide such cryosurgical device adaptedto apply low temperatures to opthalmic tissues. A further object is toprovide such a cryosurgical device having a double-walled Dewar andprobe assembly insulated by a common vacuum.

The cryosurgical device of, this invention comprises athermally-insulated refrigerant storage container and an elongatedthermally-insulated probe connected to the container. The container hasa scalable opening providing access to the interior for filling thecontainer with a vaporizable liquid refrigerant. A major portion of theinterior of the container is filled with porous material that is adaptedto hold a vaporizable liquid refrigerant. The probe extends outwardlyfrom the container and comprises an enclosed thermally conductive tipmember attached at the outer end, a refrigerant supply tube extendingfrom the container interior into the tip member, and an enclosedrefrigerant exhaust tube extending from the tip member to an exterioroutlet provided therefor in a wall of the container. The container isadapted for attachment to a pressurizing device so that liquid storedwithin the porous material can be pressurized, transferred into theprobe to the tip member and then exhausted.

The preferred refrigerant is liquid nitrogen which has a suitably lowboiling point and is inert. The pressurizing gas is also preferablynitrogen gas. Other low boiling cryogens may be suitable.

The container preferably comprises a double-walled vessel having aninner vessel, a larger outer jacket gastightly enclosing the innervessel with an evacuated insulating space between the outer surface ofthe inner vessel and the inner surface of the outer jacket, and anaccess tube extending across the insulating space and gas-tightlyconnected to a wall of the inner vessel and to a wall of the outerjacket in communication with the aforementioned scalable opening. Theporous material can be of a porous nature capable of either adsorbing avaporizable liquid refrigerant such as synthetic crystalline zeolites,or by holding a vaporizable liquid refrigerant by capillary action, suchas a monolithic porous mass of sand-lime (calcium silicate) as describedin U.S. Patent 2,883,040.

The probe is preferably insulated by an evacuated space enclosed by anelongated, gas-tight shell that encloses the aforementioned refrigerantsupply tube and refrigerant exhaust tube, and which extends from theprobe tip member to the container outer jacket such that therefrigerative effects of the vaporizable liquid refrigerant are confinedto the probe tip member. The probe refrigerant supply tube andrefrigerant exhaust tube may be positioned concentrically orlongitudinally adjacent within the probe.

The cryosurgical device of this .invention has made possible theclinical development of new cryosurgery techniques for retinaldetachment and lens extraction in the human eye by employing the lowtemperatures of cryogens such as liquid nitrogen. This device has anultra-low temperature capacity which permits a rapid rate of cooling inexcess of 15/sec. A minute warming coil may be incorporated into theprobe tip member to provide warming rates in excess of l5/sec. Theserapid rates permit precision control in the uniform application of cold.When employed as an opthalmic cryosurgery device, the probe tip employedis curved to p'ermitcorrect angulation and application of the freezingtemperature to the desired location on the eye. The entire device issufliciently compact to enable a surgeon to hold the device in his handand yet the refrigerant capacity of the device is suflicient for even aprotracted surgical procedure. The figure shows a preferred embodimentof the cryosurgical device of this invention. Thermally insulatedrefrigerant storage container 10 comprises an innervessel 12, a largerouter jacket 14 gas-tightly enclosing the inner vessel with an evacuatedinsulating space 16 therebetween. An access tube 18 extends acrossinsulating space 16 at one end of container 10 and gas-tightlyconnectsone end of inner vessel 12 to an adjacent end of outer jacket14, the latter containing a scalable opening 20 closed by threaded cap22. Access tube 18 is preferably constructed in the form of bellows, asshown, to provide a longer heat leak path and to allow for any relativeexpansion or contraction between the inner vessel 12 and the outerjacket 14. For greater protection against heat leakage evacuated space'16 may be filled with an opacified insulation such as described in U.S.Patent 2,967,752 or 3,007,596. A vacuum of less than about 1 micronmercury may be maintained when the inner vessel 12 is cold by asynthetic crystalline zeolite absorbent material, such as described inU.S. Patent 2,900,800, positioned in gas communication with evacuatedspace 16. In addition, a palladium oxide getter material may be providedin gas communication with evacuated space 16 to remove traces ofhydrogen gas. Outer jacket 14 may be provided with a bursting disk and avacuum pinch-off tube. Inner vessel 12 is substantially completelyfilled with a calcium silicate porous material 24. Porous material 24 isprovided in a plurality of sections, two being shown, 'separated byporous means such as screens 26 which extend transversely across theinterior of inner vessel 12. Screens 26 have a relatively coarse meshon' the order of about 50 mesh. Screens 26 serve the function ofproviding low pressure drop sections through which the porous material24 can be uniformly and fully saturated with the vaporizable liquidrefrigerant when container'ltl is filled. At the end of inner vessel 12opposite access tube 18 several screens 30 are superimposed in staggeredrelation to prevent particles of the porous material 26 from beingpassed beyond the storage space within inner vessel 12 that is occupiedby the porous material 24. Screens 30 are of a relatively fine mesh onthe order of 240 mesh.

An elongated space 32 axially aligned with access tube 18 passes throughscreens 26 and porous material 24 so that a refrigerant filling tube maybe inserted through access tube 18 into inner vessel 12 in closeproximity to screens 30 for filling and saturating porous material 24with liquid refrigerant. The cross sectional area of porous material 24is preferably slightly smaller than the cross sectional area of innervessel 12 such that an outer annular space 34 is provided between theouter surface of porous material 24 and the inner vessel 12. As liquidrefrigerant is transferred into inner vessel 12, it will dis- :perseinfo elongated space 32 and an annular space 34 and thence into thesections of the porous material 24 primarily through screens 26. Afterthe porous material 24 has been saturated with the liquid refrigerant,the filling tube would be withdrawn and the sealable opening 20 closedby cap 22. The liquid refrigerant will remain suspended within porousmaterial 24 until driven otf by the addition of heat or pressureregardless of the attitude of container 10.

Probe 36 comprises a refrigerant supply tube 38, a

tip member 40, refrigerant exhaust tube 42 and an enclosing elongatedshell 44. Supply tube 38 gas-tightly extends th-rough the end of innervessel 12 opposite the access tube 18 into tip member 40. Exhaust tube42 is gas-tightly connected to tip member 40 and concentrically enclosesthe portion of supply tube 38 adjacent the tip member 40. Toward theinner end of supply tube 38, supply tube 38 passes gas-tightly throughthe wall of exhaust tube 42 and the latter extends non-concentricallyand gas-tightly into inner vessel 12, through a space 28 providedtherefor in porous material 24, and through evacuated space 16 adjacentto access tube 18 to an exterior outlet 46 provided therefor in outerjacket 14. The probe outer shell 44 is connected gas-tightly to tipmember 40, enclosing supply tube 38 and exhaust tube 42, and is extendedto the outer jacket 14 of container and gas-tightly connected theretosuch that space 48 within the outer shell 44 is in gas communicationwith evacuated space 16 of container 10.

Tip member 40 is preferably curved as shown when the cryosurgical deviceof this invention is to be used in performing opthalmology operations sothat the pointed projection 50 on tip member 40 can be convenientlypositioned against the portion of an eye on which the operation isperformed. Other tip configurations of course may be employed dependingupon the type of cryosurgery to be performed.

The exhaust tube 42 is preferably coiled within evacuated space 12surrounding access tube 18 so that any residual refrigerative effects ofthe exhaust refrigerant may be employed to cool that portion ofevacuated space 12.

The cryosurgery device depicted in the figure is provided with apressurizing tube 52 which is gas-tightly connected to inner vessel 12and outer jacket 14 to provide a means for pressurizing the interior ofthe inner vessel 12. Pressurizing tube 52 is preferably coiledconcentrically with exhaust tube 42, as shown, such that incomingpressurizing gas through pressurizing tube 52 can be cooled by theresidual refrigerative effects of exhaust gas passing out throughexhaust tube 42.

The cryosurgical device of this invention is preferably operated in thefollowing manner. The porous material 2 is filled with liquid nitrogenin the manner described in a preceding paragraph. A pressurizing gas isthen transferred into inner vessel 12 through pressurizing tube 52 at atemperature above the temperature of the liquid nitrogen within porousmaterial 24. The pressurizing gas withgas to the probe tip member 40 byway of supply tube .38

and then to exhaust from the device by way of exhaust tube 42. If thepressurizing gas is initially at about ambient temperature, the heatexchange arrangement between exhaust tube 42 and pressurizing tube 52will lower the temperature of the incoming pressurized gas to belowabout --40 F. The temperature of tip member 40 is monitored by athermo-couple (not shown) attached to tip member 40 and the temperatureof tip member 40 may be controlled by controlling the flow rate ofpressurizing gas into the cryosurgery device. A relatively high flowrate of pressurized gas will result in greater evaporation of liquidnitrogen within porous material 24 and hence the gas reaching tip member40 will be colder.

What is claimed is: a

1. A cryosurgical device which comprises a thermallyinsulatedrefrigerant storage container having a sealable opening providing accessto the interior of the container for filling said container with avaporizable liquid refrigerant; non-metallic porous material positionedwithin the interior of said container and adapted to hold a vaporizableliquid refrigerant in the liquid phase; a thermallyinsulated probeconnected to said container and extending outwardly therefrom comprisinga hollow, thermallyconductive tip member, an enclosed refrigerant supplytube extending from the interior of said container into the tip member,and an enclosed refrigerant exhaust tube extending from said tip memberto an exterior outlet provided therefor m a wall of said container; anda pressurizing conduit joined to said container in fluid communicationwith said non-metallic porous material for introducing pressurized fluidto vaporize said liquid refrigerant for flow to said probe.

2. A cryosurgical device according to claim 1 wherein the probe supplyand exhaust tubes extend concentrically into said probe tip member; andwherein said supply tube extends gas-tightly through the wall of saidexhaust tube toward said container; and wherein said probe supply andexhaust tubes extend gas-tightly and nonconcentrically into saidcontainer.

3. A cryosurgical device according to claim 1 wherein said porousmaterial comprises a monolithic calcium silicate filler.

4. A cryosurgical device according to claim 1 wherein said porousmaterial is capable of holding said vaporizable liquid refrigerant inthe liquid phase by capillary action.

5. A cryosurgical device which comprises a refrigerant storage containerhaving an inner vessel, an outer jacket gas-tightly enclosing said innervessel and spaced therefrom to provide an evacuated space between theinner vessel outer surface and the outer jacket inner surface, asealable opening in the outer jacket Wall providing access to the innervessel for filling said inner vessel with a vaporizable liquidrefrigerant; a bellows-type access tube within said evacuated spacebeing gas-tightly connected to the walls of said inner vessel and outerjacket and having a first end in fluid communication with said sealableopening; non-metallic porous material positioned within said innervessel so as to fill a major portion thereof, being in fluidcommunication with a second end of said access tube and adapted to holdsaid vaporizable liquid refrigerant in the liquid phase; athermally-insulated probe gas-tightly connected to said container andextending outwardly therefrom comprising a hollow thermally-conductivetip member, an enclosed refrigerant supply tube having one end in fluidcommunication with said non-metallic porous material in said innervessel and another end extending through said evacuated space into saidtip member, an enclosed refrigerant exhaust tube positioned to extendfrom said tip member through said evacuated space; an exterior outletthrough said outer jacket wall being joined to an end of said exhausttube in said evacuated space; and a pressurizing conduit having one endextending through the outer jacket wall and said evacuated space, andthe other end extending through the inner vessel wall in fluidcommunication with said non-metallic porous material for introducingpressurized fluid to vaporize said liquid refrigerant and flowrefrigerant vapor to said probe.

6. A cryosurgical device according to claim 5 wherein said porousmaterial comprises a monolithic calcium silicate filler.

7. A cryosurgical device according to claim 5 wherein said probeincludes an outer shell enclosing the probe supply and exhaust tubes andgas-tightly joining said tip member and said container outer jacket suchthat the space between the probe outer shell and the probe supply andexhaust tubesis in gas communication with the container evacuated space.

8. A cryosurgical device according to claim 5 wherein a plurality ofscreens extend transversely across said inner vessel to divide theporous material therein into axiallyadjacent sections; and wherein thecrosssectional area of said porous material is less than thecross-sectional area of the inner vessel interior such that an annularspace is provided between the inner surface of said inner vessel and theouter surface of said porous material, said plurality of screensextending into said annular space.

9. A cryosurgical device according to claim 8 wherein said porousmaterial is provided with an elongated space axially of said access tubewhich extends through said screens and said adjacent sections of porousmaterial.

10. A cryosurgical device according to claim 5 wherein said pressurizingconduit is coiled around said access tube within said evacuated space;and wherein the probe refrigerant exhaust tube extends through saidinner vessel tube in heat exchange adjacency with said pressurizingconduit.

References Cited UNITED STATES PATENTS 1,516,437 11/1924 Humpoletz.1,815,570 7/1931 Jones. 2,883,040 4/1959 Pater et al 2067 OTHERREFERENCES I.A.M.A. Cryogenic Surgery of the Basal Ganglia, 128- 401,pp. 600-604, author I. S. Cooper, September 1962.

RICHARD A. GAUDET, Primary Examiner.

into said evacuated space and is coiled around said access 15 MCNEILL,Assistant Examiner-

1. A CRYOSURGICAL DEVICE WHICH COMPRISES A THERMALLYINSULATEDREFRIGERANT STORAGE CONTAINER HAVING A SEALABLE OPENING PROVIDING ACCESSTO THE INTERIOR OF THE CONTAINER FOR FILLING SAID CONTAINER WITH AVAPORIZABLE LIQUID REFRIGERANT; NON-METALLIC POROUS MATERIAL POSITIONEDWITHIN THE INTERIOR OF SAID CONTAINER AND ADAPTED TO HOLD A VAPORIZABLELIQUID REFRIGERANT IN THE LIQUID PHASE; A THERMALLYINSULATED PROBECONNECTED TO SAID CONTAINER AND EXTENDING OUTWARDLY THEREFROM COMPRISINGA HOLLOW, THERMALLYCONDUCTIVE TIP MEMBER, AN ENCLOSED REFRIGERANT SUPPLYTUBE EXTENDING FROM THE INTERIOR OF SAID CONTAINER INTO THE TIP MEMBER,AND AN ENCLOSED REFRIGERANT EXHAUST TUBE EXTENDING FROM SAID TIP MEMBERTO AN EXTERIOR OUTLET PROVIDED THEREOF IN A WALL OF SAID CONTAINER; ANDA PRESSURIZING CONDUIT JOINED TO SAID CONTAINER IN FLUID COMMUNICATIONWITH SAID NON-METALLIC POROUS MATERIAL FOR INTRODUCING PRESSURIZED FLUIDTO VAPORIZE SAID LIQUID REFRIGERANT FOR FLOW TO SAID PROBE.